ML20086H714
| ML20086H714 | |
| Person / Time | |
|---|---|
| Site: | Peach Bottom  |
| Issue date: | 07/01/1975 |
| From: | Cooney M PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Anthony Giambusso Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20086H716 | List: |
| References | |
| AO-75-49, NUDOCS 8401200137 | |
| Download: ML20086H714 (2) | |
Text
i C
PHILADELPHIA ELECTRIC COMPANY 2301 MARKET STREET
\\
\\
PHILADELPHIA. PA.19101
's Mr. A. Giambusso, Di rector Division of Reacter Licensing l
Offic~c of Nuclear Reactor Regulation's United States Nuclear Regulatory Commission Washington, D.C.
20555
Dear Mr. Giambusso:
Subject:
Abnormal Occurrence The following occurrence was reported to Mr. Jim Partlow, Region 1, Office of Inspection and Enforcement, United States Nuclear j
Regulatory Comission on June 21, 1975 Written notification was made to Mr. James P. O'Reilly, Office of Inspection and Enforcement, Region 1, Uni ted States Nuclear Regulatory Commission on June 23, 1975.
In accordance wi th Section 6.7.2.A of the Technical Specifica tions, Appendix A of DPR-44 for Unit 2 Peach Bottom Atomic Power Station, the following occurrence is being submitted to the Directorate of Reactor Licensing as an Abnormal Occurrence.
Reference:
License Number DPR-44 Technical Speci fication
Reference:
3.5.A Report No.:
50-277-75-49 Report Date:
July 1, 1975 Occurrence Date: June 21, 1975 Facility:
Peach Bottom Atomic Power Station R.D. //1, Del ta, Pennsylvania 17314 l
Identi fica tion of Occurrence:
Failure of operator motor on RHR system valve M0-2-10-1543.
Conditions Prior to Occurrence:
Reactor shutdown and depressurized.
Description of Occurrence:
l During the use of the RHR system in the shgtdown cooling mode, the 154B valve was positioned manually from the control room to adjust flow. During this operation it was noted that the limi t. lights on the valve indica ted an abnormal condi tion. An inspection of the valve re-vealed that the stem anti-rotation key had fallen out, resulting in rotation of the stem. This rotation without valve translation upset the calibration of, the operator. Apparently the stem anti-rotation key had become jamed between the anti-rotation arm and the packing follower
~
0401200137 750701 PDR ADOCK 05000277 71gf S
r
( )L.
lPlagn 2h277-75-49 Mr.- A. G i ambus so July I, 1975
^
o which resulted in excessive load being applied to the motor as it attempted to move the stem.
This, in turn, caused the motor to fail electrically.
Designation of Apparent Cause of Occurrence:
The probable cause of this occurrence is excessive vibration of the valve during. shutdown cooling operations.
In this mode, the valve is operated in a throttling condition in an attempt tn reduce shutdown cooling f low to 'a minimum. The throttling condi tion causes significant vibration of the valve limitorque' operator and motor.
Analysis of Occurrence:
Safety significance of this incident is minimal since the reactor was shutdown and depressurized.
Shutdown' cooling was still available to the reactor through the
'A' RHR luop and if needed, the 1548-valve could have been positioned manually from the operator.
~
Corrective Action:
The valve, stem anti-rotation arm was 'ositioned and the key p
replaced and locked. The valve motor was shipped back,to the manu-facturer for repair. The stator is being rewound End a new rotor is being manuf actured.
Completion of valve repair work is expected by July 1, 1975 1
The system was returned to service with the valve in its normal operating node - fully open. Additionally, the valve has been locked in this position to assure its availability for service.
The PORC re-viewed the procedure relating to the operation of this system without l,
the 1548 valve motor and concluded that the system is fully operabic.
Failure Data:
t
'Previously reported Abnormal Occurrences 277-74-32, 277-75-5, and 278-74-35 Very truly yours,
/
M M.
. Cooney Ass t Gen't Superintendent Generation Division Mr. J. P. O'Reilly, Director, Region I cc:
l Office of Inspection and Enforcement l
United States Nuclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 l
\\
t
.